Linux Distros Unpatched Vulnerability : CVE-2026-45895

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(317694);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/05/29");

  script_cve_id("CVE-2026-45895");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-45895");

  script_set_attribute(attribute:"synopsis", value:
"The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be
patched.");
  script_set_attribute(attribute:"description", value:
"The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied
patch available.

  - In the Linux kernel, the following vulnerability has been resolved: quota: fix livelock between quotactl
    and freeze_super When a filesystem is frozen, quotactl_block() enters a retry loop waiting for the
    filesystem to thaw. It acquires s_umount, checks the freeze state, drops s_umount and uses
    sb_start_write() - sb_end_write() pair to wait for the unfreeze. However, this retry loop can trigger a
    livelock issue, specifically on kernels with preemption disabled. The mechanism is as follows: 1.
    freeze_super() sets SB_FREEZE_WRITE and calls sb_wait_write(). 2. sb_wait_write() calls
    percpu_down_write(), which initiates synchronize_rcu(). 3. Simultaneously, quotactl_block() spins in its
    retry loop, immediately executing the sb_start_write() - sb_end_write() pair. 4. Because the kernel is
    non-preemptible and the loop contains no scheduling points, quotactl_block() never yields the CPU. This
    prevents that CPU from reaching an RCU quiescent state. 5. synchronize_rcu() in the freezer thread waits
    indefinitely for the quotactl_block() CPU to report a quiescent state. 6. quotactl_block() spins
    indefinitely waiting for the freezer to advance, which it cannot do as it is blocked on the RCU sync. This
    results in a hang of the freezer process and 100% CPU usage by the quota process. While this can occur
    intermittently on multi-core systems, it is reliably reproducing on a node with the following script,
    running both the freezer and the quota toggle on the same CPU: # mkfs.ext4 -O quota /dev/sda 2g && mkdir
    a_mount # mount /dev/sda -o quota,usrquota,grpquota a_mount # taskset -c 3 bash -c while true; do
    xfs_freeze -f a_mount; \ xfs_freeze -u a_mount; done & # taskset -c 3 bash -c while true; do quotaon
    a_mount; \ quotaoff a_mount; done & Adding cond_resched() to the retry loop fixes the issue. It acts as
    an RCU quiescent state, allowing synchronize_rcu() in percpu_down_write() to complete. (CVE-2026-45895)

Note that Nessus relies on the presence of the package as reported by the vendor.");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/security/cve/cve-2026-45895");
  script_set_attribute(attribute:"solution", value:
"There is no known solution at this time.");
  script_set_attribute(attribute:"agent", value:"unix");
  script_set_attribute(attribute:"risk_factor", value:"Medium");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");
  script_set_attribute(attribute:"vendor_unpatched", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/05/27");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/05/29");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:10");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-64k");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-64k-core");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-64k-debug");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-64k-debug-core");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-64k-debug-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-64k-debug-devel-matched");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-64k-debug-modules");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-64k-debug-modules-core");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-64k-debug-modules-extra");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-64k-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-64k-devel-matched");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-64k-modules");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-64k-modules-core");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-64k-modules-extra");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-abi-stablelists");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-core");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-debug");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-debug-core");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-debug-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-debug-devel-matched");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-debug-modules");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-debug-modules-core");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-debug-modules-extra");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-debug-uki-virt");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-devel-matched");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-doc");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-modules");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-modules-core");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-modules-extra");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-modules-extra-matched");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-rt");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-core");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-debug");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-debug-core");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-debug-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-debug-modules");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-debug-modules-core");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-debug-modules-extra");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-modules");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-modules-core");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-modules-extra");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-rt-core");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug-core");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug-kvm");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug-modules");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug-modules-core");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug-modules-extra");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-rt-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-rt-kvm");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-rt-modules");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-rt-modules-core");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-rt-modules-extra");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-tools");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-tools-libs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-tools-libs-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-uki-virt");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-uki-virt-addons");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-zfcpdump");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-zfcpdump-core");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-zfcpdump-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-zfcpdump-devel-matched");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-zfcpdump-modules");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-zfcpdump-modules-core");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-zfcpdump-modules-extra");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:libperf");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:perf");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:python3-perf");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:rtla");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:rv");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Misc.");

  script_copyright(english:"This script is Copyright (C) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info2.nasl", "set_linux_os_id.nasl");
  script_require_keys("Host/cpu", "Host/local_checks_enabled", "global_settings/vendor_unpatched", "Host/OS/identifier");
  script_require_ports("Host/OS/Red Hat Enterprise Linux-10");

  exit(0);
}

if (!get_kb_item("global_settings/vendor_unpatched")) exit(0, "Unpatched Vulnerabilities Detection not active.");
if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (empty_or_null(get_one_kb_item("Host/RedHat/rpm-list"))) audit(AUDIT_PACKAGE_LIST_MISSING);

include('linux_unpatched.inc');

var distro_constraints_array = {
  "Red Hat Enterprise Linux-10": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "10",
        "pkgs": [
          {"reference": "kernel"},
          {"reference": "kernel-64k"},
          {"reference": "kernel-64k-core"},
          {"reference": "kernel-64k-debug"},
          {"reference": "kernel-64k-debug-core"},
          {"reference": "kernel-64k-debug-devel"},
          {"reference": "kernel-64k-debug-devel-matched"},
          {"reference": "kernel-64k-debug-modules"},
          {"reference": "kernel-64k-debug-modules-core"},
          {"reference": "kernel-64k-debug-modules-extra"},
          {"reference": "kernel-64k-devel"},
          {"reference": "kernel-64k-devel-matched"},
          {"reference": "kernel-64k-modules"},
          {"reference": "kernel-64k-modules-core"},
          {"reference": "kernel-64k-modules-extra"},
          {"reference": "kernel-abi-stablelists"},
          {"reference": "kernel-core"},
          {"reference": "kernel-debug"},
          {"reference": "kernel-debug-core"},
          {"reference": "kernel-debug-devel"},
          {"reference": "kernel-debug-devel-matched"},
          {"reference": "kernel-debug-modules"},
          {"reference": "kernel-debug-modules-core"},
          {"reference": "kernel-debug-modules-extra"},
          {"reference": "kernel-debug-uki-virt"},
          {"reference": "kernel-devel"},
          {"reference": "kernel-devel-matched"},
          {"reference": "kernel-doc"},
          {"reference": "kernel-modules"},
          {"reference": "kernel-modules-core"},
          {"reference": "kernel-modules-extra"},
          {"reference": "kernel-modules-extra-matched"},
          {"reference": "kernel-rt"},
          {"reference": "kernel-rt-64k"},
          {"reference": "kernel-rt-64k-core"},
          {"reference": "kernel-rt-64k-debug"},
          {"reference": "kernel-rt-64k-debug-core"},
          {"reference": "kernel-rt-64k-debug-devel"},
          {"reference": "kernel-rt-64k-debug-modules"},
          {"reference": "kernel-rt-64k-debug-modules-core"},
          {"reference": "kernel-rt-64k-debug-modules-extra"},
          {"reference": "kernel-rt-64k-devel"},
          {"reference": "kernel-rt-64k-modules"},
          {"reference": "kernel-rt-64k-modules-core"},
          {"reference": "kernel-rt-64k-modules-extra"},
          {"reference": "kernel-rt-core"},
          {"reference": "kernel-rt-debug"},
          {"reference": "kernel-rt-debug-core"},
          {"reference": "kernel-rt-debug-devel"},
          {"reference": "kernel-rt-debug-kvm"},
          {"reference": "kernel-rt-debug-modules"},
          {"reference": "kernel-rt-debug-modules-core"},
          {"reference": "kernel-rt-debug-modules-extra"},
          {"reference": "kernel-rt-devel"},
          {"reference": "kernel-rt-kvm"},
          {"reference": "kernel-rt-modules"},
          {"reference": "kernel-rt-modules-core"},
          {"reference": "kernel-rt-modules-extra"},
          {"reference": "kernel-tools"},
          {"reference": "kernel-tools-libs"},
          {"reference": "kernel-tools-libs-devel"},
          {"reference": "kernel-uki-virt"},
          {"reference": "kernel-uki-virt-addons"},
          {"reference": "kernel-zfcpdump"},
          {"reference": "kernel-zfcpdump-core"},
          {"reference": "kernel-zfcpdump-devel"},
          {"reference": "kernel-zfcpdump-devel-matched"},
          {"reference": "kernel-zfcpdump-modules"},
          {"reference": "kernel-zfcpdump-modules-core"},
          {"reference": "kernel-zfcpdump-modules-extra"},
          {"reference": "libperf"},
          {"reference": "perf"},
          {"reference": "python3-perf"},
          {"reference": "rtla"},
          {"reference": "rv"}
        ]
      }
    ]
  }
};

var distro_constraints_values = linux_unpatched::get_distro_constraints(distro_constraints_arr:distro_constraints_array);
if (empty_or_null(distro_constraints_values)) audit(AUDIT_HOST_NOT, 'affected');
var report = linux_unpatched::check_unpatched_constraints(distro_constraints_values:distro_constraints_values);

if (!empty_or_null(report))
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_WARNING,
      extra      : report
  );
  exit(0);
}
else
{
  audit(AUDIT_HOST_NOT, 'affected');
}